1. Field of the Invention
The present invention relates to a fuel injection apparatus in which fuel within a fuel tank is boosted by a fuel pump, and the boosted fuel is injected and supplied to an engine via a fuel injection valve attached to a throttle body, and more particularly to a throttle body for a two-wheeled vehicle provided with a fuel injection valve preferably used for the two-wheeled vehicle.
2. Description of the Conventional Art
A description will be given of a conventional throttle body for a two-wheeled vehicle with reference to FIGS. 2 and 3.
Reference numeral 1 denote a throttle body in which a suction air passage 2 is provided so as to pass through an inner portion. The suction air passage 2 is opened and closed by a butterfly type throttle valve 4 attached to a throttle valve shaft 3 which is rotatably supported to the throttle body 1 across the suction air passage 2.
The suction air passage is sectioned into a downstream side suction air passage 2a and an upstream side suction air passage 2b by the throttle valve 4. The downstream side suction air passage 2a is connected to an engine by a suction air pipe (not shown) or the like, and the upstream side suction air passage 2b is connected to an air cleaner (not shown). Accordingly, a foreign material is removed by the air cleaner, and a clean air in which an amount is controlled by the throttle valve 4 is supplied to the engine via the suction air pipe.
On the other hand, a fuel injection valve J is attached to an outer periphery of the throttle body 1.
The fuel injection valve J is structured such that a valve body opens and closes an injection hole Jb open to a leading end portion Ja on the basis of a current application to a coil in an inner portion and a current shutting, thereby injecting the boosted fuel from the injection hole Jb in a vapor form, as has been known from Japanese Patent No. 3049576 or the like.
The fuel injection valve is obliquely arranged at an acute angle with respect to a longitudinal axis Z-Z of the suction air passage 2, the leading end portion Ja thereof is inserted to a discharge opening hole 5 provided in the throttle body 1, the rear end portion Jc thereof is inserted to a fuel distribution pipe 6 screwed into the throttle body 1, and the fuel injection valve J is held by the throttle body 1 and the fuel distribution pipe 6 in this state. This is executed by screwing a collar portion 6a of the fuel distribution pipe 6 to the throttle body 1.
The discharge opening hole is open to the suction air passage 2a in the downstream side of the throttle valve 4 from a lower side, and a fuel spray escaping hole 7 is continuously provided toward an engine side end surface 1a of the throttle body 1 from the discharge opening hole 5. The fuel spray escaping hole 7 is necessary for supplying a vapor-formed fuel Jd injected from the injection hole Jb of the fuel injection valve J into the suction air passage 2a with an improved vapor form without coming into collision with the other elements.
In accordance with the structure mentioned above, the discharge opening hole 5 and the fuel spray escaping hole 7 are formed and opened so as to face to a lower position of the suction air passage 2a in the downstream side of the throttle valve 4.
In the two-wheeled vehicle, the throttle body 1 mentioned above is duct-connected by the suction air pipe (not shown) and a tubular rubber mount 8 (shown by a single-dot chain line in the drawing), and an upstream side of the rubber mount 8 is fitted to an engine side mounting pipe sleeve 9 of the throttle body 1 formed in the outer periphery of the suction air passage 2a in the downstream side than the throttle valve 4.
Further, the engine side mounting pipe sleeve 9 is formed in the throttle body 1 including the discharge opening hole and the outer periphery of the fuel spray escaping hole 7, and is formed in a complete round shape having a radius R on the basis of a center 9a which is eccentrically arranged at a distance a downward from a center Za of the suction air passage 2 formed in a complete round shape.
The above structure can be understood by FIG. 3.
The single throttle body 1 is provided with the fuel injection valve J formed in the manner mentioned above, and a multiple throttle body is formed by arranging a plurality of the throttle bodies 1 in a side direction at a fixed mounting pitch. At this time, longitudinal axes X-X of the respective throttle valve shafts 3, 3, . . . in the respective throttle bodies 1, 1, . . . are coaxially arranged in the side direction in the drawing. (This structure is shown in FIG. 4, and four axes are arranged in the side direction.)
Further, coupling levers 11a and 11b are attached to facing end portions 3a and 3b of the respective throttle valve shafts 3 and 3 in the adjacent throttle bodies 1 and 1, and the coupling levers 11a and 11b are synchronously connected by a synchronizing mechanism 12 such as a synchronizing screw or the like.
A specific structure of the synchronizing mechanism 12 is omitted for clarifying the drawing, however, is provided with a mechanism of synchronously rotating the adjacent throttle valve shafts 3 and 3 and adjusting opening degrees of the throttle valves 4 and 4 attached to the respective throttle valve shafts 3 and 3 to an identical opening degree.
In other words, the respective throttle valve shafts 3, 3, . . . of the respective throttle bodies 1, 1, . . . are synchronously rotated by the coupling levers 11a and 11b and the synchronizing mechanism 12, and the opening degrees of the respective throttle valves 4 attached to the respective throttle valve shafts 3, 3, . . . are synchronously controlled to the identical opening degree.